Recently there has developed a need for coating compositions which are both storage stable and curable at relatively low temperatures in short periods of time. Substrates coated with such compositions may be processed in a more energetically efficient manner in shorter processing times.
U.S. Pat. No. 3,383,937 discloses the use of imidazoles such as 2-ethyl-4-methyl imidazole, 2-hexyl-4-phenyl imidazole, benzimidazole and others as curing agents for polyepoxides. The compositions of U.S. Pat. No. 3,438,937 generally having curing times of several hours at temperatures of 40.degree. to 300.degree. C., preferably 50.degree. to 250.degree. C.
U.S. Pat. No. 3,383,433 discloses the use of a mixture of phenolic novolac resin and an azole as a curing agent for polyepoxide resins. The compositions of U.S. Pat. No. 3,383,433 generally cure at temperatures of about 125.degree. C. to about 175.degree. C. for two hours.
Japanese Kokai 51[1976]-93,999 discloses the use of 1,2,4-triazoles, substituted by certain groups such as --CONH.sub.2, as curing agents for epoxy resins. These substituted triazoles are merely mixed at room temperature with the epoxy resins in epoxide curing amounts. The epoxy resins which contain these curing agents are hardened by heat treatment at 50.degree.-200.degree. C. in 1-20 hours.
An object of the present invention is to provide storage stable, azole-functional resins which can be used to prepare coating compositions. Other objects of the present invention are to provide storage stable coating compositions which can be cured at low temperatures in short time periods.
Accordingly, there have been found storage stable coating compositions prepared from new azole-functional resins which can be cured at low temperatures in short time periods to produce films that resist organic solvents, are relatively hard, and have a high degree of gloss.